Summary

Adding a team user group with more users than the plan allows, to an individual account repository, is failing without giving a notification to the user for the reason of failure

Steps to Reproduce

1. Create a Bitbucket account that is a on 5 user plan
2. Create a repository under this individual account
3. Create a Team with this account
4. Create a 'User Group' in the team you just created
5. Add 6 users to this user group
6. Go back to the repository you created in step 2 >> Settings >> User and group access
7. Attempt to add the User group you created before

Expected Results

The user group should not be added, and a notification should be shown to the customer, explaining that:
The user is attempting to add more users than their billing plan allows – they need to upgrade their plan in order to do so.

Actual Results

The user group is not added, and no notification is shown to the user, to explain why this action is failing.